Field of the Invention
The present invention relates to a position determining device, position determining method, lithographic apparatus, and method for manufacturing an object.
Description of the Related Art
An exposure apparatus that transfers a pattern, such as a circuit pattern, to a substrate aligns the substrate before conveyance in order to convey the substrate to a predetermined exposure position. One example exposure apparatus forms a V-shaped cut, called a notch, in the substrate, determines the position of the substrate by detecting the position of the notch, and aligns it so as to correct position deviation from a predetermined position.
However, due to resist leakage into the notch portion or asymmetry of the substrate having the notch, a performance failure of a semiconductor device tends to occur in a region around the notch in steps, including an exposure step and a film formation step. To address this issue and also prevent a decrease in yield, a technique for aligning a substrate having no notch is needed.
Japanese Patent Laid-Open No. 2007-5794 relates to an alignment device having a mechanism of determining a position of a substrate by using a mark on the back surface of the substrate. It determines the position of the substrate by using a sensor for detecting an edge of the substrate and a sensor for detecting the mark on the back surface.
Japanese Patent Laid-Open No. 9-139342 also relates to an alignment device having a mechanism of determining a position of a substrate by using a mark on the back surface of the substrate. It determines the position of the substrate by receiving light reflected from a shot array formed on the front surface of the substrate and light reflected from the mark on the back surface of the substrate by a single image pickup element.
In the alignment device described in Japanese Patent Laid-Open No. 2007-5794, the sensor for detecting the edge and the sensor for detecting the mark are spaced apart from each other. Thus it is necessary to measure relative positions of the two sensors in advance. If an ambient temperature change is large, it may be necessary to frequently measuring the relative positions.
The alignment device described in Japanese Patent Laid-Open No. 9-139342 includes no unit configured to detect an edge. Accordingly, if edge exposure processing of exposing an edge portion along an edge in order to remove unnecessary resist on the substrate is needed, it is necessary to newly detect the edge.